There are many applications in optics and other fields where it is desirable to provide alignment information or relative motion tracking information in all six spatial degrees of freedom (DOF) for one or more locations on a body. In such case, there are a variety of metrology options to measure the displacement and orientation of the locations of interest. These options include isolated contact probes (such as feeler gauges, and linear voltage differential transform gauges), holography, auto-collimators, interferometers, capacitance distance measuring interferometers, laser tracking systems, etc.
The measurement is more challenging, when it must be done with limited access to locations on a body of interest. For example, in situ testing on a factory floor or integration of components is typically a situation in which access to a body or a component is limited. Under such condition, use of a coordinate measurement machine (CMM) where a body is entirely surrounded or scanned by a calibrated contact or non-contact probe is not feasible or practical.
In addition, it is difficult to measure relative motion between large bodies in a confined space with little real estate available for metrology components. Measurement of relative motion is even more difficult, if not impossible, when knowledge of motion in six degrees of freedom (DOF) is necessary.
The present invention addresses the above problems by providing a system and method for measuring displacement and orientation in six spatial DOF between two separate bodies.